1. Field of the Invention This invention is generally directed to sweeping machines of the type used in industrial areas and in parking lots and more specifically to sweeping or cleaning machines which are specifically designed to be powered and transported by conventional forklifts. The invention incorporates a hydraulically powered sweeping machine wherein hydraulic power to the motors and fan units is derived directly from a hydraulic system mounted thereto which is controlled by an operator from the forklift. In addition, the sweeping machine includes a main support frame for supporting the components of the sweeping machine relative to a surface being swept and which frame also acts as a hydraulic fluid reservoir. The sweeping machine is designed to permit not only sweeping but filtering of air which has been swept into the unit's hopper so that dust is not recirculated within a confined shop or industrial space and thus facilitates working conditions in such areas.
2. History of the Related Art
Due to the ever increasing awareness of the need to preserve good environmental conditions in industrial areas and work shops and the like, a great deal of inventive effort has been directed to facilitate the manner in which such areas are treated not only to remove dirt and debris but also to such machines which have the ability to protect air quality by filtering the air which is passed through such machines during use. An early example of a mechanized cleaning device for use in industrialized areas is disclosed in U.S. Pat. No. 2,283,229 to Richards. This patent discloses a manually maneuvered sweeping machine which includes a motor driven cylindrical brush which sweeps debris from the surface into a bin after which air within the machine passes through filter elements suspended above the bin before the air is exhausted to atmosphere. To provide cleaning in edge or corner areas, the unit also incorporates a forward leading offset rotary brush which acts to sweep debris from corners and edge wall areas toward the central portion of the cleaning machine where such debris will be acted upon by the primary cylindrical brush. Unfortunately, such a machine which is manually maneuvered is not adequate nor efficient for cleaning large industrial spaces as the machine is limited in size so as to be easily handled by an individual. Further, such a machine would require a great deal of manual effort to discharge dirt and debris which has been collected by removing the collection bin from the machine and thereafter manually dumping the material therefrom afterwhich, the bin must be remounted to the machine.
In order to overcome the disadvantages of smaller manually maneuvered cleaning machines, a number of patents have been directed to providing sweepers which may be attached to other prime movers. For instance, in U.S. Pat. No. 3,950,811 to Larson, a sweeper attachment is disclosed which is designed to be maneuvered by a forklift by being directly attached to the under frame or chassis of the forklift truck. The unit includes a cylindrical sweeper brush mounted within a housing which is powered by mechanical connection to support wheels also mounted within the sweeper housing. Unfortunately, with this kind of unit, the power to the brush is determined by the surface contact of the wheels with the surface being cleaned. This type of power is not sufficient to adequately clean shop areas, driveways, parking lots and related surfaces especially under conditions wherein surfaces are not level. In addition, the unit must be designed to be raised from a surface when the a forklift is moved in a sideways direction in order to prevent damage to the wheels and brush of the unit. Also, the unit must be manually disengaged from the forklift in order to permit dumping of debris from the unit's collection receptacle. Dust and other materials meanwhile are collected on oil pads. The collection of dust ladened air on oily surfaces does not provide adequate filtration to promote a safe environment and is therefore not adequate.
In order to increase maneuverability of industrial sweepers of the type which are powered by a secondary prime mover, U.S. Pat. No. 4,214,338 to Kyle discloses an industrial sweeper which may be directly mounted to the lift forks of a forklift truck. This type of unit however utilizes a sweeper which is powered by a mechanical drive connection to the support wheels of the sweeping apparatus and therefore relies on the rotation of the support wheels to generate power to the sweeping brush. As with other types of industrial sweepers which utilize ground contact to generate power, such power generation is not sufficient to adequately clean industrial areas especially when surface areas are irregular.
Additional industrial sweeping machines which are specifically designed to be supported and manipulated by conventional industrial forklift trucks are disclosed in U.S. Pat. No. 4,675,935 to Kasper et al. and U.S. Pat. No. 4,819,290 to Schulte. In Schulte, a single rotary brush is powered by a hydraulic motor so as to sweep debris into a collection bin which may be tipped when the unit is raised by the forklift mechanism of the forklift truck. There is, however, no provision for powering the unit utilizing any controls from the forklift and the unit is fixedly secured to the forks of the forklift and therefore is not independently vertically adjustable with respect thereto so as to permit the unit to follow varying contours in the surface areas which are being swept. Likewise, in Kasper et al., the unit is not free to float vertically relative to the forklift mechanism of the forklift truck and therefore cannot follow irregular surface contours. Also, the unit in Kasper et al. does not provide an easy means for allowing debris to be discharged from the machine after an area has been cleaned.
An additional example of prior art industrial sweepers which are designed to be maneuvered by a separate vehicle is disclosed in U.S. Pat. No. 4,001,908 to Franklin.